The present invention relates to a cigarette-type smoking article having a heat conductive, preferably metallic enclosure therein. This article preferably produces an aerosol that resembles tobacco smoke and most preferably contains no more than a minimal amount of incomplete combustion or pyrolysis products.
The use of metallic enclosures in cigarette-type smoking articles is known. For example, in British Pat. No. 956,544, there is described a proposed cigarette-type smoking article having a steel tube combustion cartridge. This cartridge is filled with charcoal treated with KClO.sub.3 or KMnO.sub.4.
Ellis et al. (Ellis I), in U.S. Pat. No. 3,258,015 describes a proposed cigarette-type smoking article utilizing a heat conductive (metal) tube as a container for their aerosol forming materials. Heat from the burning fuel source surrounding the tube caused volatilization of the materials contained therein. Similar devices are described in Synectic British Pat. No. 1,185,887.
Likewise, in Steiner, U.S. Pat. No. 4,474,191, proposed smoking articles are described in which the mainstream aerosol comprised volatile and/or sublimable materials disposed within a channel separated from the heat source. A heat conductive member was used to transfer heat from the burning fuel to this aerosol generating means.
Ellis et al. (Ellis II), in U.S. Pat. No. 3,356,094, described a modification to their original design to eliminate the heat conducting metal tube which ultimately protruded from the lighting end of their smoking article as the fuel was consumed. The new design proposed a heat conductive tube made out of a material, such as certain inorganic salts or an epoxy bonded ceramic, which became frangible upon heating.
Kaswan, in U.S. Pat. No. 4,027,679, describes a cigarette having disposed therein a ceramic or metallic smoke vector, open at the lighting end and sealed at the mouth end. This vector is said to reduce the draw heat of the article, thereby reducing the amount of pyrolysis products in the aerosol.
Levavi, in Canadian Pat. No. 687,136 described proposed cigarettes with tubes, some of which were metal and some of which burned slowly, for controlling the amount of tars and nicotine delivered to the user.
Many other cigarette-type smoking articles have been proposed through the years, especially over the last 20 to 30 years.
For example, U.S. Pat. No. 4,079,742 to Rainer et al.; U.S. Pat. No. 4,284,089 to Ray; U.S. Pat. No. 2,907,686 to Siegel; U.S. Pat. No. 3,738,374 to Bennett; U.S. Pat. No. 3,516,417 to Moses; U.S. Pat. Nos. 3,943,941 and 4,044,777 to Boyd et al.; U.S. Pat. No. 4,286,604 to Ehretsmann et al.; U.S. Pat. No. 4,326,544 to Hardwick et al.; U.S. Pat. No. 4,340,072 to Bolt et al.; and European Patent Appln. No. 117,355 to Hearn, each describe cigarette-type smoking articles, but none of these articles have ever achieved any degree of commercial success.
Thus, despite decades of interest and effort, there is still no smoking article on the market which provides the benefits and advantages associated with conventional cigarette smoking, without delivering considerable quantities of incomplete combustion and pyrolysis products.